In a related art, a method of measuring an electric field intensity distribution or directivity of an antenna in a near field using a vector network analyzer (VNA) has been proposed (see, for example, Patent Document 1). As illustrated in FIG. 14, an antenna 220 that is a measurement target that is detachable from a port of a transmission device 210, and a movable measurement antenna 230 are connected to a VNA 200. The VNA 200 causes a radio signal for test to be transmitted from the antenna 220 and compares the radio signal with a radio signal received by the measurement antenna 230 such that an amplitude and a phase of an electric field radiated from the antenna 220 can be simultaneously measured.
However, in recent years, a type of a transmission device that includes an antenna including a large number of antenna elements, such as a multi input multi output (MIMO) antenna, in which the antenna is not detachable from the transmission device due to a request for an increase in the number of antenna elements or miniaturization of the device, or the like is widely used. The measurement method for a single entity of an antenna using a VNA as described above cannot be applied to the antenna of such a transmission device.